# Linear Rule

## Linear Rule

Expression that defines a relationship of direct variation.

relationship of direct variation is defined by a rule in the form y = kx where k is a constant.

### Example

This graph illustrates the function f defined by f(x) = –2x. In this case, the constant k is –2.

We can also represent a linear relationship using a table of values:

 x -5 -2 0 1 3 f(x) 10 4 0 -2 -6